Simply put, buy the Axioms, more detail and tighter sounding bass, IMO. Are the Axiom's worth $1000 more, only you can make that decision, for some they wouldn't be, to me they are, the better sub alone is worth the extra costs.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70